Rigid, dimensionally stable polyurethane foams and a process for the production of such foams in which the foam pressure is reduced

Abstract

Rigid foams are made by reacting a polyisocyanate with an isocyanate-reactive composition which includes at least one isocyanate-reactive compound, preferably, an amine-initiated polyol and more preferably, an amine-initiated polyether polyol and a second, different polyol in the presence of a blowing agent composition which includes water and a catalyst composition which includes two different blowing catalysts, preferably, pentamethyldiethylenetriamine and bis(2-dimethylamino-ethyl)ether.

What is claimed is:  
     
       1. A process for the production of a rigid dimensionally stable polyurethane foam comprising reacting 
       a) an organic isocyanate  
       with 
       b) an isocyanate-reactive compound  
       in the presence of 
       c) a blowing agent comprising water and  
       d) a catalyst composition comprising at least two different blowing catalysts in which the catalyst composition comprises pentamethyldiethylene triamine and bis(2-dimethylaminoethyl)ether.  
     
     
       2. The process of  claim 1  in which the catalyst composition includes from about 0.02 to about 1.0 parts by weight of each of the blowing catalysts. 
     
     
       3. The process of  claim 1  in which the catalyst composition comprises from about 0.2 to about 0.3 parts by weight of each blowing catalyst. 
     
     
       4. The process of  claim 1  in which b) comprises an amine-initiated polyol. 
     
     
       5. The process of  claim 4  in which b) further comprises a second polyether or a polyester polyol. 
     
     
       6. The process of  claim 1  in which blowing agent mixture c) further comprises a hydrocarbon, an HCFC, an HFC or a combination thereof. 
     
     
       7. The process of  claim 1  in which up to 7% by weight, based on the total weight of b)+c)+d), of water is included in blowing agent c). 
     
     
       8. The process of  claim 1  in which the amine-initiated polyol is an o-toluenediamine-initiated polyether polyol. 
     
     
       9. The process of  claim 1  in which the isocyanate reactive compound is a polyether polyol and a polyester polyol. 
     
     
       10. A process for the production of a rigid, dimensionally stable polyurethane foam comprising reacting 
       a) an organic isocyanate  
       with 
       b) an isocyanate-reactive composition comprising an amine-initiated polyol and a second isocyanate-reactive compound  
       in the presence of 
       c) a blowing agent comprising water and  
       d) a catalyst composition comprising pentamethyldiethylene triamine and bis(2-dimethylaminoethyl) ether.  
     
     
       11. A rigid polyurethane foam produced by the process of  claim 1 . 
     
     
       12. A rigid polyurethane foam produced by the process of  claim 10 . 
     
     
       13. A water heater insulated with the foam of  claim 11 . 
     
     
       14. A water heater insulated with the foam of  claim 12 .